1. Field of the Invention
This invention relates to semiconductor diode lasers.
2. Description of Related Art
In a semiconductor diode laser radiation is produced in an active region of the diode structure and it is normally required to direct the radiation into an output lightguide, such as an optical fibre.
The active region is normally part of a layer of semiconductor material which is sandwiched between other layers of semiconductor material which may readily be arranged to consist of material having a refractive index different from that of the material of the sandwiched layer so as to confine the radiation to the firstmentioned layer. However, it is more difficult to provide such optical confinement in the plane of the layer containing the active region which is necessary to obtain efficient coupling to the light waveguide.